Shock absorber



SHOCK ABSORBER R. H. wHlsLER, JR., ET A1.

Sgpt. 29, 1953 Patented Sept. 29, 1953 SHOCK ABSORBER Ralph H. Whisler, Jr., and Dale A. Pahner, Monroe, Mich., assignors to Patent Development Company, Monroe, Mich., a partnership Application December 17, 1949, Serial No. 133,522

(Cl. 18S-88) 6 Claims.

This invention relates to shock absorbers and more particularly to a novel, hydraulic, directacting, shock absorber.

The shock absorber of this invention is of the tubular type which includes a uid containing pressure cylinder and a reserve chamber. A piston assembly is slidably disposed in the pressure cylinder and one end of the pressure cylinder is closed by means of a base compression valve which controls the ow of fluid between the :pressure cylinder and reserve chamber, in order to compensate for piston rod displacement in the pressure cylinder. Both the piston assembly and the compression valve assembly include orifice means for normally by-passing iluid from one side of the assembly to the other, during movement of the piston assembly in one direction or the other. The assemblies also include valve means for controlling the flow of fluid through the assemblies in accordance with fluid pressure. Means are provided in each of the assemblies for at least partially closing the orice means prior to actuation of the valve means of the assembly, so that at relatively low fluid pressures orifice control in the shock absorber is provided, while at higher fluid pressures .pressure valve control is provided. That is, the shock absorber or" this invention incorporates diminishing orifice means which aid in the provision of a better and smoother operating shock absorber. Thus, with the shock absorber of this invention eiiicient control is provided for both high and low shock absorber iiuid pressures and velocities, thus providing a better ride in a vehicle, on which the shock absorber is mounted, on both smooth and irregular road surfaces.

It is therefore an object of this invention to provide a shock absorber of the aforementioned type, which is constructed so as to provide eicient shock absorber control irrespective of the uid pressure or velocity therein.

It is a still further object of this invention to provide a shock absorber of the aforementioned type, which, when mounted on a vehicle, will provide a better vehicle ride over both smooth and irregular road surfaces.

It is a still further object of this invention to .provide a shock absorber of the aforementioned type, which is relatively simple in construction, durable in use, eicient in operation, and positive in control.

These and other objects of this invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawing, in which:

Figure 1 is a longitudinal sectional view of the shock absorber of this invention; and

Figure 2 is a sectional view of the structure illustrated in Figure 1, taken along the line 2 2 thereof.

Referring now to the drawing, it will be seen that the shock absorber includes a pressure cylinder 5 and a reserve tube l, which is concentric with the pressure tube 5 and cooperates with the latter to provide a reserve chamber in the shock absorber. The lower end of the reserve tube l is closed by means of a suitable closure member 9, having a fitting II connected thereto for attaching one end of the shock absorber to a vehicle or any other suitable device. The upper end of the reserve tube i is closed by means of a suitable closure member I3, having a central aperture I5 therein, for a use which will hereinafter appear. A piston assembly Il is slidably disposed in the pressure cylinder 5, and the pressure cylinder and reserve tube are adapted to contain hydraulic fluid in a conventional manner, The piston assembly Il includes a piston body I9 and a rod 2|. The lower end of the rod 2l is connected to the piston in body I9, in a manner which will be hereinafter described, and the upper end of the rod extends through a closure and sealing assembly 23, which is connected with the upper end of the pressure tube 5 and engages the closure member I3 of the reserve tube l. The piston rod extends through the aperture I5 in the closure member I3 and has a dust tube assembly 25, and an attaching fitting 27 connected therewith, in any suitable manner. The attaching fitting 2l is adapted to be connected to a portion of a vehicle or other suitable device so that upon relative movement of the sprung and unsprung portions of a vehicle or device, the piston assembly I9 will move relatively to the pressure cylinder 5 and reserve tube l. The lower end of the pressure cylinder 5 is closed by means of a base compression valve assembly 29 which communicates with the pressure cylinder as well as the lower portion of the reserve chamber, and is adapted to control the ilow of fluid between the pressure cylinder and the reserve chamber, as will hereinafter appear.

The piston rod 2I is provided with a transversely extending aperture SI intermediate the ends thereof, and above the piston body I9. A longitudinally extending passageway 33 communicates with the passageway 3i and is enlarged intermediate the ends thereof to provide a plunger or valve seat 35. The piston rod is also provided with a transversely extending passagewhich terminates adjacent the upper end ofthe. plunger and the lower end of which extendsV through the bottom of the plunger. When the plunger shoulder 4| is in engagement withthe seat 35, the upper end of the plungeris disposed in the piston rod transversepassageway 3| and the plunger groove 42 is in alignment or registry with the piston rod transverse passageway31. A' stud 45 is threaded into the lower end of the enlarged portion of thepistonrod :passageway 33 and is provided with a-shoulder '41, which abutsV against-the bottom of the piston rod. The stud 45 has a-longitudinally extending aperture 4E)4 therethrough, which communicates at the upper end with the piston rod passageway 33 and at the lower end with the pressure cylinder. A coil spring 5| is disposed between the upper end of the stud 45. and the shoulder 4| on the plunger 39, so as to resiliently retain the plunger shoulder 4| in engagement with the plunger seat 35 oftheV piston rod.

The piston body I9k is provided with an outer set of circumferentiallyfspaced, vertically extending passageways 53: andan inner set-of circumferentially spaced passageways 55. The outer set of passageways 53 have their upper ends normally closed by meansof a disk 51 which rests upon radially spaced lands 59 formed on the top surface of the piston body |9. The disk` 51 is resiliently held in a closed position by means of'a star spring 6|, which isloaded'by means of a flanged collar member 63, disposed between .the top surface of the piston bodywand-'the under side of the stud shoulder 41. to be moved off of its-seat byv fluid pressure flowing upwardly through the passageways 53 `during downward movement of Ithe pistonassembly, as will hereinafter appear. The lowerendsv of the piston passageways lare'normallyf closedby' means of laminated disks 61,which rest upon radially spaced lands 69-on .the bottom `surface of the central piston body portion. The disk-s are resiliently held in engagement with the lands- 69 by means of a anged` collar member 1|-and a-coil spring 13 which is disposedbetween thefunder side of the member 1|-and the headof a nut15 which is threaded on .the lower endo` the-stud-45. The nut 15-secures the piston rod-to the piston body. |9 and securesthe entire piston assembly in the desired relationship, while at the same time loading the coil spring 13, so -as to apply a predetermined resilient pressureagainst the disks 61. The disks {i1-are adapted to :be moved off; of their seats or lands 694 by fluid pressure flowing through the passageways 55 during upward movement of the piston assembly, and the plungerv39 is adapted to be moved downwardly against the action of its coilspring 5|,.s0 as to move the groove 42 and passageway 43 `thereof out of registration with the piston rod passageway 31 and thereby close off the passageway 31 against the` flow of fluid therethrough and through the stud passageway 49 to the opposite sideof Vthe pistonassembly, during upward movement of the piston,

The disk 51 is adaptedas will hereinafter appear. It should, however, be pointed out, and will hereinafter more fully appear, that the valve disks 61 will not move off of their piston body lands 69 until after the plunger 39 has been moved downwardly at least a predetermined amount so as to at least partially close off the orice. In certain instances it may be desirable that the orifice. be completely closed before the disks are moved off'of their seats, and in other instances it may be desirable that the disks move off their seat when the orifice is Yonly. partially closed.

The base compression valve assembly 29 includes a: valve body 16 having an outer set of circumferentially spaced passageways 11 therethrough and an inner set of circumferentially spaced passageways 19. The valve body is also provided'wth a central bore or aperture 8|, in which is disposed a tubular valve cage member 83. The valve cage member 83 has an enlarged head portion 85, which rests upon the topsurfaceof the valve body 16. recessed at -81 to provide a valve seatl'atl the lower end thereof. Slidably mounted in the re'- cess S1 is a hexagonal shaped valve member 9|v having an annular shoulder 93 -on the-lower sur-v face thereof, which is adapted to rest` upon the.

valve seat 89. A washer 95- is disposed inthe upper end of the recess 81 andthe topof'theA iently held in engagement with the washer 95 by f means o a coil spring 99 disposed in the enlarged portion of a passageway |0| extending through the valve cage 85. As can be seen in Fig; 2 when th-e valve member 9| is in its-uppermost position fluid can flow from the pressure' cylinder through the spaces between the flat portions of the hexagonal periphery of the valve member and the inner periphery of the wall of the recess 81, thus providing a normally open` once through thecompression valve assembly 29; from the pressure cylinder to the reserve chamber.

The upper ends of the compression valve openmgs 11 are normally closed by means of'a disk- |03 engaging lands |05 -on the top surface of the valve body 16. The disk |03 is resiliently loaded through a star spring |01 which in turn is loaded and held in position by the headportion 850i` the valve cage. The lower ends of the valve body passageway 19 are normally` closed by a stackpf disks |09 which engage an annular land |||.on the bottom of the central portion of the valve body 16. The disks are held in positionand are loaded by spinning over the bottom portion of the valve cage at ||3. During downward movement of the piston assembly I1, at low pressures, fluid can flow past the valve member 9| and through the valve cage passagewaysv |0'| into the reserve chamber, thus providing an orifice between the pressure cylinder and reserve chamber.

member 9| will be moved downwardlyuntil it engages the valve cage seat 09, at which time the:

orifice will be closed and fluid cannot pass from the pressure cylinder to the. reserve chamber` until sufficient pressure-is built up Itovmove the: .valve disksVv |09 off their'seat' and p ermit fluldf However; inper- The cage head portion is- How-` ever, as the fluid pressure increases, the valve-l This,of course, canbee controlled by varyingthe resistance of sprinz:

99 and the loading of disks |09. During upward movement of the piston assembly |1, fluid can flow from the reserve chamber to the pressure cylinder so as to keep the same continually filled, through the Valve passageway 11 and past the valve disk |05, which is loaded only very lightly through the star spring |01.

When the shock absorber is mounted between the sprung and unsprung portions of an automotive vehicle, or some other suitable device, relative movement of these portions will cause movement of the piston assembly |1 in the pressure cylinder 5. When the piston assembly |1 moves downwardly in the pressure cylinder 5, at a very low velocity and therefore without building up very much iiuid pressure in the pressure cylinder, between the piston assembly |1 and the base valve assembly 29, iiuid can flow past the compression Valve member 9| through the valve cage passageway ill and into the reserve chamber. As the velocity of the piston assembly increases and the fluid pressure increases, the valve member 9| will be moved downwardly so as to either partially or completely close oi the passageway |0| against the ow of fluid. When suflicient pressure is built up, the valve disks |09 will be moved off of their seat by the fluid pressure flowing through the passageway 19 so as to permit fluid to flow from the pressure cylinder to the reserve chamber. The flow of fluid from the pressure cylinder to the reserve chamber is, of course, caused by piston rod displacement which results in fluid flowing through the piston passageways 53 and past the valve disk 51. Thus, on the compression stroke of the shock absorber orice control is provided during relatively low piston velocities and low fluid pressures, so as to remove any harshness from the shock absorber action during such low velocities. If the orifice were not provided fluid could not flow from the pressure cylinder to the reserve chamber until the valve disks |09 were moved oii of their seat. As a result, harshness in the ride of the vehicle would occur when the same was driven over very smooth roads. As the orifice is either completely or partially closed, when the piston velocity and fluid pressure pass a predetermined value, the valve disks |09 primarily control the flow of fluid from the pressure cylinder to the reserve chamber when the vehicle is being driven over relatively irregular roads, so that the proper control is provided under these conditions, as well as under smooth riding conditions, thus providing the desired control under all vehicle riding conditions.

During the rebound movement of the piston assembly I1, that is upward movement of the same, at relatively low velocities and low fluid pressures, fluid can flow through the piston rod passageway 31, plunger passageways 43 and 45 and through the stud passageway 39, to the lower side of the piston assembly, thus providing orifice control when the vehicle is moving over relatively smooth pavement. However, as the piston Velocity, and thus the fluid pressure in the upper portion of the pressure cylinder, increases, the plunger 39 will be moved downwardly by the fluid pressure acting on the upper portion thereof, so as to gradually close the orifice by moving the plunger passageway 43 out of registration with the piston rod passageway 31. After the orifice is either partially or completely closed, or the plunger passageway 43 moved partially or completely out of registration with the piston rod passageway 31, all or the majority of the 6 fluid will flow from the upper portion of the pressure cylinder to the lower portion thereof through the piston passageways 55. Thus, at higher piston velocities and fluid pressures, the disks 61 primarily control the shock absorber rebound action, and thus properly dampen the vehicle spring action. As the piston assembly moves upwardly in the pressure cylinder, the lower portion of the pressure cylinder is replenished by fluid flowing from the reserve chamber through the compression valve passageways 11 and past the disk |03.

Thus, duringboth the compression and rebound strokes of the shock absorber, orifices are provided for taking any harshness out of the shock absorber action and providing the necesv sary and desirable control, but as the piston velocity and lluid pressure in the shock absorber increase, the orifices are diminished, i. e., either partially or completely closed so that the valve disks primarily control the shock absorber. The shock absorber of this invention therefore provides a smooth vehicle ride for both smooth road conditions and irregular road conditions, and eliminates harshness, which has been present 1n heretofore known shock absorbers, under either one or the other of these conditions.

What is claimed is:

l. A shock absorber including a pressure cylinder adapted to contain fluid, a piston assembly slidably disposed insaid pressure cylinder including operating rod means and a piston body connected with said rod means adjacent one end thereof, said rod means having passageway i means therein to permit fluid to flow from one vin said operating rod means to permit uid to pass therethrough, resilient means normally supporting said plunger in said rod means so that the passageway means thereof are in registration with the rod means passageway means, said plunger means being actuable by fluid pressure in said pressure cylinder during movement of said piston in one direction so as to cause said plunger means passageway means to move at least partially out of registration with said rod passageway means and thereby prevent or at least reduce the dow of fluid from one side of said piston to the other, and additional valve means associated with said piston body normally preventing the now of fluid from the one side of said piston body to the other side thereof, and being actuable by fluid pressure after said plunger passageway means are moved at least partially out of registration with said rod passageway means to primarily control the flow of fiuid from one side of said piston body to the other.

2. A shock absorber including a pressure cylinder and a reserve chamber adapted to contain fluid, a piston assembly in said cylinder, a valve assembly closing one end of said pressure cylinder and controlling the flow of fluid between said'pressure cylinder and reserve chamber, said valve assembly including a valve body, said valve body having a passageway therethrough permitting the flow of fluid from said pressure cylinder to said reserve chamber during movement of said piston assembly in one direction, one end of said passageway being enlarged to provide a recess having a valve seat, a valve member slidably mounted in said recess and shaped so as to permit iiuid to flow between said member and the I perlpheryiofzsaidrecess, resilient means ,normallyV retaining saidl valve member s off j of saidi recess being actuable after said valve memberz approaches said seat vto .primarily control' the-fl'ow of fluid'y fromzsaidppressure: cylinder'v to said reserve chamber.

3; Axshockabsorber includinga'pressure cyl-v inder and a reserve, chamber adapted to containfluid-,2a valve assembly controlling; communication' between vsaid i pressurei cylinder. and reservechamber, a piston assemblyslidably disposedin;

said,` pressure cylinder, means providingan ori-v ceiin ysaidpiston assembly normally permitting the; flow of. fluid romone, side ofsaid piston assemblyto the other side Athereof 'during movementfofl saidv pistonfassemblyv in one direction, a

normally'open elementactuable by fluid pressure to close the saidzorice Aas the fluid pressure increases and reaches a predetermined value, resilient-means for retaining said element insaid normally open position but permitting the same to .moveto said closed position under said predetermined fluid pressure, a passageway in said piston assembly and Valve means normally preventing-the flow of fluid through said passage-- way; from oneside of said piston to the other side thereof, when said piston moves in said one direction, said ,valve means being actuable by fluid pressure only after said orifice is at least partially closed.

4. A' shock absorber including a pressure cylinder, and a reserve chambery adapted to contain fluid, a piston assembly slidably disposed in said pressurecylinder and adapted to control the ow of fluid from one side thereof to the opposite side thereof during relative movement between said piston assembly and pressure cylinder, a valve assembly controlling communication between said pressure cylinder and reserve chamber, means providing an orifice in said valve assembly. normally permitting the flow of rluid from one side of said valve assembly to the other side thereof during movement of said piston assembly in one direction, a valve element actuable by uid pressure so as to close said orifice as the fluid pressure increases, resilient means for retaining said :valve element in said normally open position but permitting the saine to move to its closed position under said predetermined iiuid pressure, valve means in said valve assembly normally preventing the flow of fluid from one side of said valve assembly to the other side thereof when said piston assembly moves in said one direction, said valve means being actuable by fluid pressure only after said orice is at least partially closed; .so as to `thereby' 'control the flow. of fluidT from one-side of said valve'assembly to the .othex sidethereof;

5. A shockpabsorbersincluding. a pressure; cyl-..

, inder and a reserve-chamber adaptedfto contain fluid Zvalve means controlling communication abetween said pressure cylinderV andrreserve cham@4 berra piston,assembly-slidably disposed insald pressure;cylinder, means providing an orifice in, saidw pistonv assemblyV normally permitting the:

flowr of fluid from'one side;off saidtpiston'to the: other side thereoff' during movement of saidpise ton in-one direction in" said'v pressure cylinder,l normally open velocity responsivecmeans inf-said; pistonassembly including an element andA resil ient means normally retainingsaldv element in; an'. open position relative to Asaid-y orifice adaptedl togradually close saidforice as the velocity oftsaid'4 piston increases, a passageway in said ,piston'asr semblythrough which fluid; can'flow from one` side of said pistonassembly to the otherypresg sure responsive means-normally closing. said-pas,-V

'sageway against the-flowfof fluid therethrough` duringv movement of -said piston assembly in said: onedirection.

6.` An shock absorber Vincludinga-pressure` cyl?v inderfand-a reserve-chamber adapted-to contain fluid, apiston assembly slidably disposed; in said; pressure cylinderand controlling the flovvofzfluidV from one side vto the other thereof duringv movement of said piston in said pressure cylinder, a. valve assembly controlling the flow of fluid-be-A tween said pressure cylinder` and reservel cham-- ber, means providing an orice in said-.valve as,- sembly normally permittingthe flowof'fluid Afromy one side thereof to the other side during movement of said piston in onedirection, a normally. open velocity responsive element in said valveA assembly for controlling the flow of Vhuid through said orifice and adapted to close said orifice against` the flow of fluid therethrough when the; velocity` of said piston reaches a predetermined value, resilient means for retaining said element in saidfnormally open position but permitting; the same-to move to itsgclosedposition under: said predetermined fluidY velocity, andA pressure responsive means controlling the ow of` uid from-one side-.of 4-said valve assembly tothe other side thereof, said pressure responsive means ,permittingl theyflowof fluid fromone-side of said` valve assembly 'to the otheronly after the fluid, pressure reaches,k a, predetermined value.

RALPH H. WHISLERJR. DALE A. PALMER.

References Cited in the le of this patenty UNITED-STATES PATENTS Number Name Date 2,078,364 Becker et al. Apr. 27, 1937` 2,240,644A Focht May 6,- 1941v 2,355,491A WhislerA Aug. 8, 1944v 2,384,186l Magrum etl al. Sept; 4, 1945 2,403,648T Focht v July-9, 1946 2,473,643 Whisler: June'14, 1949f 

